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Burning municipal solid waste (MSW) increases CO2, CH4, and SO2 emissions, leading to an increase in global warming, encouraging governments and researchers to search for alternatives. The pyrolysis process converts MSW to oil, gas, and char. This study investigated catalytic and noncatalytic pyrolysis of MSW to produce oil using MgO-based catalysts. The reaction temperature, catalyst loading, and catalyst support were evaluated. Magnesium oxide was supported on active carbon (AC) and Al2O3 to assess the role of support in MgO catalyst activity. The liquid yields varied from 30 to 54 wt% based on the experimental conditions. For the noncatalytic pyrolysis experiment, the highest liquid yield was 54 wt% at 500 °C. The results revealed that adding MgO, MgO/Al2O3, and MgO/AC declines the liquid yield and increases the gas yield. The catalysts exhibited significant deoxygenation activity, which enhances the quality of the pyrolysis oil and increases the heating value of the bio-oil. Of the catalysts that had high deoxygenation activity, MgO/AC had the highest relative yield. The loading of MgO/AC varied from 5 to 30 wt% of feed to the pyrolysis reactor. As the catalyst load increases, the liquid yield declines, while the gas and char yields increase. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

In modern chemistry pyrolysis is the principal process and large-tonnage provider, primarily, of lower olefins - ethylene, propylene - as well as butadiene, benzene and other products. The level of efficiency of the pyrolysis process largely determines the development of the petrochemical industry in whole, therefore rationalization of the process is an ongoing task of high relevance. The aim of this work is to develop a method for increasing the efficiency of the pyrolysis for lower olefins on the base of the analysis of the mechanism of the process with the possibility of controlling it. The kinetics of the interaction of the hydrocarbons with hydrogen atoms, methyl radicals and their mixtures were determined. The data on the relative reactivity of bonds of different types in reactions with hydrogen atoms and methyl radicals and the data on the effective relative reactivity when using an inert diluent increase our knowledge of the pyrolysis of feedstock of any given composition. A method based on the influence of hydrogen on the thermal reactions of alkanes and alkenes was developed to increase the selectivity of the process for the target product (lower olefins) and to reduce the yield of the liquid products of condensation and specific energy consumption. © 2018 WIT Press. ; ACKNOWLEDGEMENTS This research was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006.

The demand for renewable energy is growing due to depletion of fossil fuels and environmental and political regulations. According to this, biomass is emerging as a natural choice due to not only being a clean energy carrier but also representing the final objective of a decarbonized society. Between the thermochemical conversion processes, pyrolysis is favoured for bio-oil production. In recent years, catalytic systems have been proposed as an encouraging way by realizing the upgrading of the biomass pyrolysis bio-oil using various catalysts. According to the literature, HZSM-5 is very well known to be the most effective catalyst for cracking or reforming bio-oil. This excellent performance of HZSM-5 has been related to the shape-selectivity, ion exchange capacity, and unique acid characteristics. On the other hand, HZSM-5 with micropores is a disadvantage that is restricted by the low mass transfer rates, mainly for large molecules. In this review, mesoporous materials including Al-SBA-15, Al-MCM-41, mesoporous aluminosilicate materials (MSU-SBEA), mordenite framework inverted (MFI) catalysts and hierarchical mesoporous Y (meso Y) as potential catalysts employed in catalytic pyrolysis in recent articles have been reviewed. The catalytic performance was assessed by analysing the composition of the products. Pyrolysis product distributions of pyrolysis and properties of bio-oil have dealt. Although the results from the experiments cannot be directly compared with each other due to the using different raw materials and applying different experimental conditions, recommendations on bio-oil quantity and quality are worth to discuss.

AbstractWastes are the most frequent "by-product" of human society. The Czech Republic still has a considerable room for energy reduction and material intensiveness of production in connection with the application of scientific and technical expertise in the context of innovation cycles. Pyrolysis waste treatment is a promising alternative to the production of renewable hydrogen as a clean fuel. It can also reduce the environmental burden and the amount of waste in the environment at the same time.This paper presents the laboratory pyrolysis experiments of peanuts crisps waste to the final temperature of 800 °C. After the pyrolysis process of the selected waste a mass balance of the resulting products, off-line analysis of the pyrolysis gas and evaluation of solid residue in terms of adsorption properties and energy production and liquid products were carried out. The highest concentration of measured hydrogen (66 vol. %) was analysed during the 4th gas sampling at the temperature varying from 750 to 800 °C.

A critical review of the methods for producing pyrolysis waste oils was carried out, the possibilities and limitations of each approach were discussed. Liquid pyrolysis products (pyrolysis oils) are promising source of valuable chemical compounds, and can be also used as a fuel. A reliable analysis of pyrolysis oils is necessary to study their component composition, basic characteristics and to select the most suitable methods for the extraction of the necessary compounds. It is known that the results of GC-MS analysis of liquid pyrolysis products are usually ambiguous: there are problems of peaks overlapping and incorrect interpretation of the data, due to the complexity of the matrix and the multicomponent composition of the object. The paper presents data on the chemical composition of pyrolysis oils obtained by elemental analysis, IR spectroscopy, NMR spectrometry, GC-MS, GC-GC/MS. Based on the presented results, pyrolysis oil usually contains aromatic compounds, water-soluble substances and hydrocarbons. It was found out that there are conflicting data on the chemical composition of the pyrolysis oils of waste tires in the scientific literature. It is proposed to carry out sequential extraction sample preparation of pyrolysis mixtures to increase the reliability and accuracy of the componential and quantitative composition of the GC-MS method. Obviously, a reliable analysis of complex pyrolysis mixtures without preliminary targeted sample preparation seems unlikely.

The European Union created a European Green Deal Program (EGDP). This program aims at a sustainable economy through the transformation of the challenges related to climate and the environment. The main goal of EGDP is climate neutrality by 2050. The increase of alternative biomass residues utilization from various food processing industries and cooperation in the energy and waste management sector is required to meet these expectations. Nut shells are one of the lesser-known, yet promising, materials that can be used as an alternative fuel or a pre-treated product to further applications. However, from a thermal conversion point of view, it is important to know the energy properties and kinetic parameters of the considered biowaste. In this study, the energy and kinetic parameters of walnut, hazelnut, peanut, and pistachio shells were investigated. The results showed that raw nut shells are characterized by useful properties such as higher heating value (HHV) at 17.8–19.7 MJ∙kg−1 and moisture content of 4.32–9.56%. After the thermal treatment of nut shells (torrefaction, pyrolysis), the HHV significantly increased up to ca. 30 MJ∙kg−1. The thermogravimetric analysis (TGA) applying three different heating rates (β; 5, 10, and 20 °C∙min−1) was performed. The kinetic parameters were determined using the isothermal model-fitting method developed by Coats–Redfern. The activation energy (Ea) estimated for β = 5 °C∙min−1, was, e.g., 60.3 kJ∙mol−1∙K−1 for walnut, 59.3 kJ∙mol−1∙K−1 for hazelnut, 53.4 kJ∙mol−1∙K−1 for peanut, and 103.8 kJ∙mol−1∙K−1 for pistachio, respectively. Moreover, the increase in the Ea of nut shells was observed with increasing the β. In addition, significant differences in the kinetic parameters of the biomass residues from the same waste group were observed. Thus, characterization of specific nut shell residues is recommended for improved modeling of thermal processes and designing of bioreactors for thermal waste treatment.